In the case of headlamps for motor vehicles, a laser can be used as a light source. By means of this laser, a converter for emitting converted light can be excited. Such a converter may, for example, comprise a crystal element of Ce: YAG, a particular form of yttrium aluminum garnet. The laser is usually used to generate light with a particularly high light intensity in a particularly narrow wavelength range. If excited, the converter emits light in another, particularly broad wavelength range, i.e., it converts the light generated by the laser. Thus, in particular, white light can be generated with, for example, a temperature of 5,500 Kelvin, which is perceived as particularly pleasant by all road users.
The light dissipated by the converter is emitted by the headlamp for generating a predeterminable light distribution on a surface area in a surrounding area of the motor vehicle. Thus, the predeterminable light distribution can be set by a control device of the headlamp, for example, by means of a pivotable micro-mirror or a mirror array, which is also referred to as a digital micromirror device. The motor vehicle can also comprise an optical detection device, by means of which, for example, other road users can be detected. The light distribution can then be set, for example, as a function of these other detected road users, so that these are preferably not blinded by the light distribution.
In general, the converter of a headlamp of a motor vehicle with a laser as a light source can be damaged by mechanical forces and aging processes, so that the operability of the headlamp and thus also of the motor vehicle is impaired. Damage can lead to eye irritation and glare in other road users.
A directional system with laser and converter for an infrared sensor is known from US 2003/0183784 A1. In the case of correct alignment, the converter is excited to emit light in a certain pattern, so that it is recognizable that the infrared sensor is correctly aligned.